Charles elterich



(No Model.) l

C. ELTERICH.

TAP AND HOLDER THEREPOR.

No. 412,952. Patented Oct. 15, 1889.'

` N. PETERS, Pimerlinhcmphmwnnhingwn. u. c.

NITED STATES PATENT OFFICE.

TAP AND HOLDER THEREFOR..

SPECIFICATION forming part of Letters Patent No. 412,952, dated ctober 15, v1889. l Application filed November 2, 1888. Serial No, 289,852. (No model.)

. To all whom it may concern:

BE it known that I, CHARLES ELTERICH, of New York, in the county and State of New York, have invented a certain new and useful Improvement in Taps, of which the following is a specification.

My improvement consists in a tap which is longitudinally grooved at a number of points from end to end, so as to have a number of isolated longitudinal ribs or salient port-ions extending from end to end, the latter being screw-threaded from end to end of the tap.

My improvement also consists in the combination, with such a tap, of a block having a screw-threaded cavity adapted to receive and hold the tap, and having combined with it a set-screw or adjustable pin capable of engaging with one of the grooves of the tap to hold it against rotation. This block may be secured in any suitable holder or chuck.

In the accompanying drawings, Figure l is a side view of a tap embodying my improvement. Fig. 2 is aview of the same and the block with which itis engaged. Fig. 3 is an end view of the tap and block. Fig. 4 is a side view of the tap and a longitudinal section of the block and holder.

Similar letters of reference designate corresponding parts in all the figures.

A designates the tap. It is formed with grooves d, which extend longitudinally of it at a number of' points from end to end. Between these grooves are a number of ribs b. These also extend longitudinally of the tap from end to end. They are shown as tapering slightly at one end; but this is not indispensable. The ribs are screw-threaded from end to end. The tap is therefore substantially uniform from one end to the other.

B designates a block, shown as of circular form, and having a smooth periphery. It may be made of any suitable metal. The center is provided with a screwthreaded hole, into which the tap may be fitted and with which the t-ap may engage. By rotating the tap within the block the tap may be made to project more or less beyond the block at the end which is to be used. When it is adjusted to the desired point, it may be secured in position by a screw or screws c, extending radially through it and engaging with one or more of the grooves a of the tap. Such screw or screws will serve to secure the tap in position relatively to the block by preventing the tap from rotating.

C O2 designate a holder, consisting of a body C and a shank or handle C2. This holder is provided with a cavity d, capable of receiving the block B, and also with a cavity d', into which the inner end of the tap A may extend. The block B may be secured in the cavity CZ of the holder by one or more screws inserted into the holder, engaging with the screw-threads in the holder and extending into the block B. It will be seen that the tap may be adjusted more or less beyond the block.

The tap described may be used at either end. If broken, the remaining part may still be used. EvenV a .short piece can be used with the block B.

It is advantageous to employ a tap only of the necessary length, because the shorter the tap the less it is subject to dangerous strains. I provide for using a tap of only the necessary length, because it can always be adjusted beyond the block B exactly to the extent that is required for any particular purpose. Moreover, it is desirable to extend simply the length of the tap, which is necessary for any desired operation, beyond the block, for the reason that thus the block may serve as a gage for the depth of the work to be performed by the tap. If the tap should be warped or bent longitudinally, this will not be so prejudicial, because as the tap may be shortened to the length necessary for operation the evils of a longitudinal bend will be reduced to a minimum, and as the tap will be held in the block close to the projecting operative portion by its own screw-threads the evils of a bend will be less than if the tap were otherwise held.

'What I claim as my invention, and desire to secure by Letters Patent, is

The com bination,with a tap screw-threaded throughout its length, of a holder having a cavity and the hollow shank, a block smooth on its periphery and having a threaded hole to receive the tap, and a screw or pin tted in the block and engaging with the tap, substantially as specified.

CHAS. ELTERICH.

Vitnesses:

S. O. EDMoNns, FEED KEMPER.

IOO 

